The present invention relates to a positioning device for aligning the relative positions of two objects or patterns with a high accuracy
Often it is desired to adjust the relative positions of two objects during a manufacturing operation using an industrial automatic assembly device or assembly robot. An example of such an operation is the mounting of an IC (Integrated Circuit) device on a printed substrate. In this operation, it is of course necessary that the two be accurately aligned Conventionally, to achieve alignment, it has been the practice to employ two video cameras, one for the IC circuit device and the other for the printed substrate. The outputs of the two video cameras are compared, and a signal representing the amount of misalignment derived therefrom which is then employed to align the two objects using a feedback servo circuit or the like.
However, in this system, there is inevitably some amount of error due to misalignment between the two video cameras and image distortion in their optical and electrical circuits. Accordingly, it is difficult to accurately align the two objects with a sufficiently high accuracy.